Abstract

Charge carriergeneration and transport in tris (2-phenylpyridine) iridium (III) doped in -dicarbazole-biphenel (CBP) thin films have been studied in terms of time-of-flight and time-resolvedphotoluminescencespectroscopies. It is found that the excitation energy rapidly transfer from CBP to , and that the charge carriers are generated on sites. With increasing concentration, the electron drift mobility is slightly decreased, while the hole transit signals become unobservable. The electron and hole transport properties of doped CBP thin films result from the energy levels of the lowest unoccupied molecular orbital and the highest occupied molecular orbital of with respect to those of CBP.